This is a great introductory bit for starting off ponies. 1.5 cm thick.
Ponies often work better in a solid bit as the extra weight is well handled by their generally shorter and thicker necks. This is a high quality stainless steel bit with smaller rings at 5 cm that offers better appearance proportion for the pony.

Offered here at TheHorseStudio.com in two sizes 10.5cm and 11.5 cm at a very reasonable price.